JP2576945B2 - Construction method of manhole combined sinking pit and cutting edge to promote sinking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a concrete shaft which is used as a shaft when constructing sewer pipes and other various pipes, and is also used as a manhole as it is. The present invention relates to a construction method of a shallow concrete shaft and a subsidence-promoting cutting edge used in the construction method.

[0002]

2. Description of the Related Art Conventionally, in this type of shaft construction method, first, a sheet pile of a length obtained by adding a root to a predetermined depth is driven in,
After excavating the inside of the pit, raising the stomach, applying a cutting beam to make a temporary retaining earth, after finishing the work in the shaft, building a manhole in the shaft, backfilling the surrounding area, and assembling the liner plate (steel segment) while digging There was a method of assembling manholes in the shaft and refilling the surrounding area after the completion of the work in the shaft, assuming temporary earth retaining, but in any case, it was necessary to excavate a shaft much larger than the outer diameter of the manhole, On soft ground and below groundwater level, auxiliary methods such as water replacement and chemical injection had to be used together.

[0003]

SUMMARY OF THE INVENTION The present invention has been developed in view of the above-mentioned circumstances, and it is a construction method that does not require the use of an auxiliary construction method when constructing a vertical shaft even on soft ground or below groundwater level. The construction method does not require temporary soil retention when constructing manholes, and the construction method does not cause bending of the cylindrical sinking block.Even if no person enters the cylindrical sinking block, it is possible to excavate earth and sand between the cutting edge and the cutting edge. It is an object of the present invention to provide a shaft construction method characterized by the following.

[0004]

According to the present invention, an appropriate number of cylindrical submerged blocks having a cutting edge slightly larger than the cylindrical submerged block are provided at the lowermost stage, and a clamshell or the like is provided inside the cylindrical submerged block. It is a middle digging method of excavating and sunk by its own weight to a predetermined depth, the first invention is to provide an appropriate number of cylindrical sunk blocks provided with a cutting edge slightly larger than the cylindrical sunk block at the bottom, A method of digging under gravity to a predetermined depth by a digging method, wherein a flexible flange for preventing intrusion in the blade is provided around the upper end of the blade, and an earth wall and a cylinder formed above the flange for preventing intrusion in the blade. This is a method of constructing a manhole / submerged sinking pit characterized by excavating and sinking while injecting self-hardening lubricating material between block-shaped sinking blocks.

[0005] A second invention is a construction method in which an appropriate number of cylindrical sunk blocks having a cutting edge slightly larger than the cylindrical sunk blocks at the lowermost stage are buried under their own weight to a predetermined depth by a digging method. Provide a flexible cutting edge intrusion prevention flange around the upper end of the cutting edge, first excavate a shallow shaft slightly larger than the cylindrical sunk block to provide a soil retaining and cylindrical liner plate, at an appropriate number of locations inside the A bend prevention guide for the cylindrical squat block is provided, and the inside of the cylindrical squat block is excavated using a clam shell or the like using the bend prevention guide as a guide, and an earth wall formed above the blade entrance prevention flange. This is a method of constructing a manhole and double sinking pit, in which a self-hardening lubricating material is injected between the slab and the cylindrical sinking block, and the sinking is carried out by its own weight.

A third invention is a construction method in which an appropriate number of cylindrical sunk blocks provided with a cutting edge one size larger than the lowermost cylindrical sunk block are sunk by gravity to a predetermined depth by a digging method. The structure of the cutting edge is a structure in which a receiving portion of a cylindrical sinking block is provided on the upper surface of an inverted L-shaped steel ring, and a reinforcing rib is provided inside the steel ring, A self-hardening lubricating material is injected between an earth wall formed at the bottom and a cylindrical settling block, and excavated while jetting compressed air or compressed water into the cutting edge to settle under its own weight. This is a construction method for the established pit.

A fourth invention relates to a cutting edge used in the embodiment of the third invention, in which a steel ring having an inverted L-shaped cross section provided with a receiving portion of a cylindrical sinking block is provided on the upper surface. For the purpose of injecting compressed air or compressed water in the circumferential direction inside the steel ring, an appropriate number of ribs for It is a blade for facilitating sedimentation provided with a pipe.

[0008] A cylindrical sinking block having a strength capable of withstanding earth pressure is excavated in the interior, and is connected to a cylindrical sinking block at an upper stage to be sunk by its own weight to a predetermined depth, thereby assisting even in soft ground or below groundwater level. A shaft can be constructed without the need for a construction method.

When excavating on soft ground or sandy ground, it is preferable to fill the inside of the tubular submerged block with water and perform underwater excavation in order to prevent boiling. After sinking to the specified depth, the concrete at the bottom is left, leaving the cutting edge as it is. When excavating underwater, concrete will be poured underwater.
After the bottom slab concrete has hardened, the water in the cylindrical sinking block is pumped up, and sewer sewers and other various pipe work are carried out in the vertical shaft using the small-diameter propulsion method.

[0010] The connecting portion of the cylindrical sinking block is welded so as not to be loosened, bent or pulled out. Therefore, a steel ring is provided at least at the end of the sinking block. A water-swellable sealing material is usually attached to the end face as a water-stopping material.

Also, by making the cylindrical sinking block made of concrete, it can be used as it is as a concrete manhole if a ladder-like step is attached.

The cutting edge used in the lowermost stage of the cylindrical submerged block is generally made of steel, and has an outer diameter slightly larger than that of the cylindrical submerged block in order to cut friction between the cylindrical submerged block and the ground during submerging. I have. Self-hardening lubricant is injected into a gap formed between the outer diameter of the cutting edge and the outer diameter of the cylindrical set block. Further, in order to prevent the self-hardening sliding material from entering the cutting edge at the time of sinking, there is provided a flexible cutting opening flange made of rubber or the like having an outer diameter larger than the outer diameter of the cutting edge.

In general, a clam shell is used to excavate the inside of the cylindrical sinking block, but it is not possible to excavate between the inner diameter of the block and the outer diameter of the block (wall thick portion). In the case of a concrete block, the wall thickness becomes 175 mm if the inner diameter of the cylindrical sinking block is 2000 mm. The cutting edge has a structure in which ribs for reinforcement are inserted into a steel ring with a thickness of about 6 mm, and piping for injecting compressed air or compressed water in the circumferential direction inside the steel ring is applied. Make small injection holes at equal intervals. This pipe is provided with a rubber hose mounting port above the cutting port, and by sending compressed air or compressed water from the ground through the rubber hose, air or water is injected from the injection hole toward the inside of the cutting port, and the wall thickness of the block is increased. It is possible to easily break down the ground left undigged in the part, and to promote the submerging of the tubular submerged block by its own weight.

[0014] The position of the piping and the injection holes to be installed in the circumferential direction inside the cutting edge are changed according to the condition of the ground. That is, in the case of soft sand ground with small particles, the piping position is near the cutting edge,
In addition, it is preferable that the injection hole be directed upward. In the case of a hard ground with remixes, it is preferable that the piping position is on the blade side and the injection hole is directed downward toward the blade edge. The injection holes are all equally spaced in the circumferential direction, and may be about 12 if the inner diameter of the cylindrical sink block is up to about 2000 mm.

A guide is provided for vertically sinking the cylindrical sinking block without bending when the sinking block is set. As a space where the guide is provided, 1 to 1.5 m is excavated and excavated in advance from the ground where the ground is relatively firm, and is buried with a liner plate one size larger than the cylindrical sunk block. If the ground in this area is weak, it is better to cast concrete on the back side of the liner plate. The cylindrical sunk block is installed in the liner plate at the same level as the center, and guides (spacers) are provided in at least three places in the space created between the liner plate and the cylindrical sunk block. It will sink vertically along.

The length of the guide is required to be about 1 m, and the material may be square material, plastic material or the like. The guide is securely attached to the liner with a jig that has processed channel material, etc.
In addition, it is preferable to adopt a structure in which the thin plate can be inserted back and forth by screws so that the adjustment can be easily performed.

When the cylindrical submerged block is submerged to a predetermined depth, a jig for preventing excessive subsidence is attached just before the predetermined depth in order to prevent further subsidence. As this jig, for example, a support frame is made of H-shaped steel or the like on a liner plate, an appropriate number of hanging metal fittings are attached to the upper part of the uppermost cylindrical sinking block, and this is fixed with a hanging rod or chain block. Things are used.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 shows an embodiment of a manhole / sinking pit according to the present invention. A cylindrical sunk block 2 is connected to a ring-shaped blade 1 by about 3 to 5 steps. A tubular liner plate 3 made of steel and retaining and assembled into a cylinder having a size slightly larger is installed on the outer periphery of the upper part to form a shaft for propulsion construction. However, FIG. 1 shows a state in which the construction of the concrete shaft according to the present invention has been completed and the manhole has been constructed, and the floor slab block 4 formed by eccentrically forming the opening 4 a is installed on the uppermost cylindrical sunk block 2. Then, a manhole block 5 continuous with the opening 4a is stacked on top of it.

As an example of the dimensions of the cylindrical sinking block 2, the outer diameter is 2350 mm, the inner diameter is 2000 mm, and the height is 100 mm.
Above and below a 0mm precast concrete block,
A 150 mm-wide steel reinforcing ring 6 is attached, and a 30 mm-wide lubricant guide groove 6 a extending in the circumferential direction and an embedding nut 7 for attaching a hanging metal fitting of the block are provided on the outer periphery, and a self-hardening lubricant is injected. An embedding nut 8 is provided for attaching a hose fixture.

The cutting edge 1 has an outer diameter slightly larger than that of the cylindrical sinking block 2, and is reinforced inside a steel ring 1b having an inverted L-shaped cross section provided with a receiving portion 1a of the cylindrical sinking block 2 on the upper surface. 2 and a suitable number of ribs 1c are provided.
As shown in FIG. 4, a rubber-made flexible blade 9 for preventing intrusion into the blade opening is mounted on the upper portion of the blade, and a pipe 1 for injecting compressed air or compressed water in the circumferential direction inside the steel ring 1b.
0 is provided, and small ejection holes 10a are provided in the pipe 9 at equal intervals in the circumferential direction. In FIG. 4, the injection hole 10a is provided on the upper side, but may be provided on the lower side or on the side depending on the state of the ground. This pipe 10 has a rubber hose 1
One attachment port 10b is provided.

FIGS. 5 and 6 show the mounting state of the bending prevention guide 12 of the cylindrical sinking block 2, which is mounted via a guide fixture 13 suspended on the liner plate 3. As the bending prevention guide 12, a square material is generally used.

Next, the construction procedure in the present invention will be described.

FIGS. 7A to 7F and FIGS. 8G to 8G.
(I) shows an example of a shaft construction procedure and a manhole construction procedure after completion of small-mouth pipe propulsion work according to the present invention.

(1) Surveying the laid position

(2) Demolition of pavement at sunk position

(3) Excavation to a depth at which it can be self-sustained at the sinking position

(4) Installation of the liner plate 3 (FIG. 7)
(See (a))

(5) Installation of the cutting edge ring 1 and the first-stage cylindrical sinking block 2, welding and mounting of a hose 14 for injection of self-hardening lubricant and a compressed air injection hose 11 (see FIG. 7B)

(6) Attaching the bending prevention guide 12 (see FIG. 7C)

(7) Installation and welding of the second-stage tubular sinking block 2 (see FIG. 7D)

(8) Excavation in the cylindrical sinking block 2 and installation and welding of the third-stage cylindrical sinking block 2 while injecting the self-hardening sliding material 16 and compressed air (see FIG. 7E).

(9) Installation of a jig for preventing subsidence ((f) of FIG. 7)
reference)

(10) After the subsidence to the predetermined position is completed, the foundation concrete is poured (see (g) of FIG. 8).

(11) Removal of jig for preventing excessive sinking

(12) Starting and arriving at the propulsion work from within the pit.

(13) Installation of the floor slab 4 (see FIG. 8 (h))

(14) Start-up of the manhole block 5 (see FIG. 8 (i))

(15) Backfilling, pulling out of the liner plate and restoring the pavement.

[0040]

Conventionally, when digging is carried out, a lubricating material such as a bentonite solution is poured outside a submerged object, and the lubricating material is discharged after submerging, and concrete is replaced in place of the lubricating material in order to facilitate subsidence. The lubricating material that was discharged was turned into industrial waste, which was a problem.

The first invention solves this problem, and uses a self-hardening lubricating material as a lubricating material.
Not only is there no replacement work, but there is no problem with industrial waste treatment. In addition, since the flange for preventing penetration into the cutting edge is provided, the self-hardening lubricating material does not flow into the cutting edge, so that there is no waste.

According to the second invention, the device for preventing bending can be easily set by assembling a liner plate at a depth of 1 to 1.5 m from the surface of the ground, and since there is no equipment on the ground, the same as the first invention. In addition to the effect, since the lining plate can be placed even during the construction, there is an effect that the traffic is released immediately if necessary and the vehicle can pass.

According to the third and fourth aspects of the present invention, by injecting compressed air or compressed water into the cutting edge, the ground in the cutting edge can be safely cut without requiring any manpower or special equipment, and the cylindrical submerged block is provided. Can be easily laid down. Also,
It is particularly effective in underwater drilling where it is difficult to check the cutting edge.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing an outline of a sinking pit according to an embodiment of the present invention.

FIG. 2 is a plan view of a blade port.

FIG. 3 is a partially cutaway side view of a cutting edge.

FIG. 4 is an enlarged sectional view of a main part of a blade port.

FIG. 5 is a partially cut-away plan view of a liner plate, a bending prevention guide, and a tubular squat block.

FIG. 6 is a longitudinal sectional view of a bending prevention guide.

FIG. 7 is a sectional view showing a shaft construction procedure in the present invention.

FIG. 8 is a cross-sectional view showing a part of a shaft construction procedure according to the present invention and a manhole construction procedure after completion of propulsion construction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cutting edge 2 Cylindrical submerged block 3 Soil retaining and cylindrical liner plate 4 Floor slab block 5 Manhole block 6a, 6b Self-hardening lubricating material guide groove 7, 8 Embedded nut 9 Flexible flange opening prevention flange 10 Pipe 11 Rubber hose 12 Bend prevention guide 13 Guide fixture 14 Rubber hose 15 Suspension bracket 16 Self-hardening sliding material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display E21D 5/04 E21D 5/04

Claims (4)

(57) [Claims] 1. A method in which an appropriate number of cylindrical sunk blocks having a cutting edge slightly larger than a cylindrical sunk block at the lowermost stage are sunk by gravity to a predetermined depth by a digging method. A flexible intrusion prevention flange is provided around the upper end, and excavation and sinking is performed while injecting self-hardening lubricant between the earth wall formed above the intrusion prevention flange and the cylindrical submerged block. A characteristic construction method of a manhole combined use sink. 2. A method in which an appropriate number of cylindrical sunk blocks having a cutting edge slightly larger than the cylindrical sunk blocks are provided at the lowermost stage by gravity digging to a predetermined depth. A flexible flange for preventing intrusion into the blade opening is provided around the upper end.First, a shallow shaft slightly larger than the cylindrical sinking block is excavated to provide a soil-cum-tubular liner plate. A bend prevention guide for the squat block is provided, and the inside of the tubular squat block is excavated using a clam shell or the like with the bend prevention guide serving as a guide, and an earth wall and a cylinder formed above the intrusion prevention flange in the blade opening. A method of constructing a manhole / submerged sinking pit, in which self-hardening lubricating material is injected between self-settled blocks and allowed to settle under its own weight. 3. A method in which an appropriate number of cylindrical sunk blocks having a cutting edge slightly larger than the cylindrical sunk blocks are provided at the lowermost stage by gravity digging to a predetermined depth. The structure is such that a receiving part of a cylindrical sinking block is provided on the upper surface of an inverted L-shaped steel ring and a reinforcing rib is provided inside the steel ring, and is formed above the flange for preventing penetration into the blade opening. Construction of a manhole / submerged pit, characterized by injecting self-hardening lubricating material between the earth wall and the tubular submerged block, and excavating and injecting compressed air or compressed water into the cutting edge to make it self-submerged. Construction method. 4. An appropriate number of ribs for reinforcement are provided inside a steel ring having an inverted L-shaped cross section provided with a receiving portion of a cylindrical sinking block on the upper surface, and a flexible member is provided on the outer periphery of the upper surface of the steel ring. And a pipe for injecting compressed air or compressed water in the circumferential direction inside the steel ring.